Architecture Technical Overview

Overview

NeXT computers were powerful and amazing computers around their time.
The orginal NeXT computers were a 25MHz 68030 computer and then later the
Turbo Series with a 66/33MHz 68040 versions were introduced. All versons
contain a Motorola DSP processor. All NeXT computers have ethernet and
SCSI2 capabilities. The color computers supported 32bit graphics. These
computers were perfection and simply the state of art.

Besides the hardware, what made these black slabs or cubes even more
impressive was the operating systems, NeXTSTEP, later known as OPENSTEP
for Mach. NeXTSTEP is a Mach kernel with a BSD 4.3 UNIX personality and
contains a rich set of object oriented libraries for rapidly developing
applications. And impressive applications like Lotus Improv and Adobe Illustrator,
were developed. Newer versions of NeXTSTEP, now controlled by Apple Computer,
Inc. will not be supported on this hardware. Also, Apple has later announced
the technical support will not support these platforms as well. This could
be possible grounds for litigation if NeXT users were so pressed.

Linux/m68k

Generally Linux/m68k runs on any MC68020 with an external MC68551
PMMU (Paged Memory Management Unit) processor. Other processors after the
MC68020 have a built-in MMU (Memory Management Unit) with exception
of the MC68EC030 and other EC processors which cannot work
with Linux/m68k. It is good to have an FPU (Floating Point Unit) or math
co-processor as it is slow to use an emulator and difficult to configure.
Commonly, MC68881 math processor is used with the MC68020
and the MC68882 is used with the MC68030. The newer MC68040
contains a built-in math coprocessor. The MC68LC040 does not have
the built-in math coprocessor.

Currently under development is the booter, used to bootstrap the operating
system as opposed to NeXTSTEP. The major obsticle to Linux/m68k is the
lack of documentation for the hardware. There is however essential information
in the older development kits. Plan9 operating system apparently supports
this platform, but the licensing restrictions are too restrictive, that
this may possibly not be used to glean important information for a port.
Once a port is making good progress, all NeXT machines will have the potential
to be supported as they all have MC68030 or MC68040 processors.

Components

Ports

NeXTstation

SCSI-2 connector (50 pin)

2 RS-423 serial ports (8 mini-din)

1 DSP port (DB-15)

1 MegaPixel Display port (DB-19)

1 Laser printer port (DB-9)

1 10Base-T Ethernet

1 Thin Ethernet, IEE 802.3a

MegaPixel Display

This monochrome diaplay is connected through the MegaPixel
display port which offers power, video display, audio input and output,
and a keyboard port. The NeXT keyboard has the connector for the mouse;
later models were compatible with the ADB (Apple Desktop Bus) specification.
Color displays did not contain the set of adapters on the back of the monitor,
for these were split off into a seperate soundbox device.

1 Headphone jack (1/8" output)

1 set of stereo Left and Right RCA jack

1 MegaPixel Display connector (DB-19)

1 Keyboard Port (5 mini-din)

1 Microphone jack (1/8" input)

NeXT Keyboard

The NeXT keyboard has a port for the NeXT bus mouse which
works similiarly to the Microsoft Bus mouse or the Macintosh Plus mouse.
The keyboard then sneds the data through its keyboard data line connected
to the MegaPixel display.

NeXT Hardware Links

These pages were created to illustrate the basic
machine information of the NeXT Family as a service to the NeXT and Linux/m68k
enthusiasts. I would deeply appreciate any suggestions people may have
regarding additional information they would like to have added. Email darknerd@mailexcite.com.